Endodontic Infections Research Articles

Genotypic Identification of Endodontic Bacteria Isolated from Berhampur, Odisha, India: First Insights

ABSTRACT Background: Endodontic infections caused by many bacterial species including Staphylococcus aureus, Klebsiella pneumonia and Salmonella enterica present a significant challenge in dental health. Accurate identification of these pathogens is crucial for effective treatment strategies. Aims and Objectives: The aim of the study was to utilize 16S rRNA genotypic analysis for the precise identification of certain bacterial strains isolated from endodontic infected tissues. Materials and Methods: Tissue samples were collected from patients with persistent endodontic infections and microbial cultures were prepared. Strains were isolated, purified. DNA extraction was performed and 16S rRNA gene amplification was carried out using polymerase chain reaction. Subsequently, the amplicons were sequenced and the sequences were compared with known reference sequences using bioinformatics programs. Phylogenetic analysis was conducted to ascertain the evolutionary relationships between the identified isolates and known strains. Results: To our knowledge, this is the first report focusing on genotypic identification of endodontic bacteria from Berhampur, Odisha, India. This study holds implications for species specific microbial ecology in dental infections facilitating quicker identification. Conclusion: Management strategies for endodontic infections may involve a systematic approach to identify, analyze and address the specific challenges such as diagnosis and endodontic emergencies, presented by each case. Focused and individualized treatment plans shall contribute to better clinical outcomes. Further detailed records can be maintained with genotype based treatment plan followed by post treatment outcomes to guide future decisions and research.

In vitro comparison to study the antimicrobial effect of silver nanoparticles gel and its various combinants as an intracanal medicament against Enterococcus faecalis.

Endodontic infections have been clearly described as biofilm-mediated infections. Bacteria and their by-products have been known to cause these infections. With the introduction of new drugs and the use of nanoparticles in recent times, there has been a significant reduction in the bacterial load in endodontic infections. The in vitro study focuses on checking the antibacterial efficacy of silver nanoparticles and its combination with other medicaments against the root canal pathogen - Enterococcus faecalis (E. faecalis). In the present study, 140 extracted human teeth were used. The teeth were sectioned, and biomechanical preparation was done. The root canals of the extracted teeth were inoculated with the culture of E. faecalis. The teeth were divided into six groups based on the intracanal medicament used: Group 1 - Silver nanocure gelGroup 2 - Silver nanocure gel + Cavisept gel (1:1)Group 3 - Silver nanocure gel + Aveu-Cal gel (1:1)Group 4 - Silver nanocure gel + Cavisept gel + Aveu-Cal gel (1:1:1)Group 5 - Positive control (specimens were inoculated with Enterococcus faecalis and left untreated to confirm the presence of infection)Group 6 - Negative control (no bacterial contamination of specimens). The colony-forming units were recorded after 48 h of incubation. The statistical analysis of the colony-forming units was done using the Kruskal-Wallis tests. Silver nanocure gel + Cavisept gel + Aveu-Cal gel (1:1:1) showed the least colony-forming units. The present study is an in vitro study, in which we concluded that the combination of all the intracanal medicaments is the best for the elimination of E. faecalis biofilm from the root canal. The above findings need to be tested in vivo also.

Comparative molecular study of Enterococcus faecalis in endodontic treatment pre and postdiode laser application

Abstract Background: Endodontic infections are polymicrobial, with the majority of bacteria being anaerobic and others being facultative. Objective: To detect and measure the level of Enterococcus faecalis in infected root canals during traditional cleaning techniques and after diode laser application by using real-time polymerase chain reaction (RT-PCR). Materials and Methods: Ninety samples were collected from 30 participant patients complaining of acute or chronic pulpitis with an age range of 18–50 years old; the teeth indicated endodontic treatment, including both anterior and posterior teeth. Thirty swabs were taken preinstrumentation, and then 30 swabs were taken after instrumentation and canal irrigation using sodium hypochlorite 5.25%, and then 30 swabs were taken in the same manner after the root canal sterilization with the diode laser. Results: This study included 30 patients with root canal infection presented with a mean age of 31.7 ± 8.6 years and a range of 18–50 years; Female patients were more than males (34.3% vs. 36.7%). The mean E. faecalis copy number was significantly reduced from precleaning status to postcleaning with sodium hypochlorite (5.25%) and postlaser therapy (P = 0.05). Conclusions: RT-PCR assay is a highly effective, dependable, and rapid technique for accurate detection and copy number counting of E. faecalis in the infected root canal; this molecular and clinical study supports the diode laser application of 940-nm WL as an adjuvant tool combined with sodium hypochlorite (5.25%) in canal disinfection during root canal treatment to reduce E. faecalis copy numbers.

Fusobacterium necrophorum predomina na microbiota do abscesso dentário mandibular em Blastocerus dichotomus

ABSTRACT: Dental abscess in ruminants is an acute polymicrobial infection, usually resulting from periodontal disease or endodontic infection, with consequences for animal health and welfare. The present study aimed to describe the bacterial microbiota of dental abscesses in Blastocerus dichotomus. Biological material from mandibular dental abscesses, punctured with a sterile syringe and needle during routine veterinary curative procedures or necropsies, was collected from three ex-situ marsh deer. Bacteria were identified using high-throughput sequencing of the 16S ribosomal RNA gene. The three specimens had the presence of facial bulging, and two died because of severe emaciation with a history of progressive weight loss. Bacteroides (38.6%), Fusobacterium (36.65%), and Porphyromonas (7.49%) represented the most abundant genera and Fusobacterium necrophorum (35.69%), Porphyromonas levii (3.12%) and Porphyromonas gulae (1.78%) were among the ten most represented species in the microbiota of mandibular abscess in Blastocerus dichotomus. These molecular findings demonstrate a broader diversity of species in the polymicrobial nature of dental abscesses in B. dichotomus than was previously reported when culture-dependent methods were used in the diagnosis.

Strategies and mechanisms targeting Enterococcus faecalis biofilms associated with endodontic infections: a comprehensive review.

Enterococcus faecalis is one of the main microorganisms that infects root canals, ranking among the most prevalent microorganisms associated with endodontic treatment failure. Given its pervasive presence in persistent endodontic infections, the successful elimination of Enterococcus faecalis is crucial for effective endodontic treatment and retreatment. Furthermore, Enterococcus faecalis can form biofilms - defense structures that microbes use to fight environmental threats. These biofilms confer resistance against host immune system attacks and antibiotic interventions. Consequently, the presence of biofilms poses a significant challenge in the complete eradication of Enterococcus faecalis and its associated disease. In response, numerous scholars have discovered promising outcomes in addressing Enterococcus faecalis biofilms within root canals and undertaken endeavors to explore more efficacious approaches in combating these biofilms. This study provides a comprehensive review of strategies and mechanisms for the removal of Enterococcus faecalis biofilms.

Poly(Lysine)-Derived Carbon Quantum Dots Conquer Enterococcus faecalis Biofilm-Induced Persistent Endodontic Infections.

Persistent endodontic infections (PEIs) mediated by bacterial biofilm mainly cause persistent periapical inflammation, resulting in recurrent periapical abscesses and progressive bone destruction. However, conventional root canal disinfectants are highly damaging to the tooth and periodontal tissue and ineffective in treating persistent root canal infections. Antimicrobial materials that are biocompatible with apical tissues and can eliminate PEIs-associated bacteria are urgently needed. Here, ε-poly (L-lysine) derived carbon quantum dots (PL-CQDs) are fabricated using pyrolysis to remove PEIs-associated bacterial biofilms. Due to their ultra-small size, high positive charge, and active reactive oxygen species (ROS) generation capacity, PL-CQDs exhibit highly effective antibacterial activity against Enterococcus faecalis (E. faecalis), which is greatly dependent on PL-CQDs concentrations. 100 µg/mL PL-CQDs could kill E. faecalis in 5 min. Importantly, PL-CQDs effectively achieved a reduction of biofilms in the isolated teeth model, disrupting the dense structure of biofilms. PL-CQDs have acceptable cytocompatibility and hemocompatibility in vitro and good biosafety in vivo. Thus, PL-CQDs provide a new strategy for treating E. faecalis-associated PEIs.

Evaluation of dental manifestations in X-linked hypophosphatemia using orthopantomography.

X-linked hypophosphatemia (XLH) is the most common inherited form of rickets. The presence of sequence variations in the phosphate regulating endopeptidase homolog X-linked (PHEX) gene is associated with increased production of fibroblast growth factor 23 (FGF23). This results in renal phosphate wasting and impaired skeletal mineralization. Spontaneous dental abscesses, caused by endodontic infections resulting from hypomineralization of dentin, are a known dental complication of XLH. There is no objective method to evaluate the severity of dentin dysplasia. The purpose of this study was to develop a quantitative method to evaluate dentin dysplasia using orthopantomography that would allow the values in patients with XLH to be compared with the values in healthy participants of the same age. The severity of dentin dysplasia was analyzed by measuring the pulp cavity area of the tooth using orthopantomographic images. The teeth analyzed were mandibular second primary molars and mandibular first permanent molars with complete root formation. Teeth with dental caries, restorations, or root resorption were excluded. This retrospective observational study included a total of 200 images of healthy participants (aged 2-15 years) divided into five age groups and 42 images of 17 patients with XLH. There was a significant tendency for the pulp cavity area to decrease with increasing age in primary and permanent teeth. The pulp chambers of patients with XLH were larger than those of healthy participants in primary and permanent teeth. We have established a method of using orthopantomography for quantitative assessment of dentin dysplasia in XLH from the primary dentition to the permanent dentition. Evaluating the severity of dentin hypomineralization by this method is useful in the diagnosis of the dental manifestations of XLH. Early diagnosis of XLH enables oral management and leads to prevention of dental abscesses.

Evaluation of the Antimicrobial Potential of Cashew Nut Shell Liquid Extract (Anacardium occidentale) against Enterococcus faecalis Strains

The resistance of microorganisms present in the root canal system is a problem associated with the failure of endodontic treatments. Therefore, the search for treatments based on herbal extracts has been an alternative to prevent persistent endodontic infections. The aim of this in vitro study was to evaluate the antimicrobial potential of cashew nut shell liquid extract (E-CNSL) against Enterococcus faecalis strains. The antimicrobial activity was evaluated using the agar well diffusion method. Petri dishes containing Mueller Hinton agar were inoculated on the surface by the microorganism using a swab, then 20 μL of the E-CNSL solution at concentrations of 500 μg/mL and 1000 μg/mL was aseptically deposited in the wells of the inoculated media. The plates were incubated at 37 °C for 24 hours. All the strains studied showed an inhibition halo ≥6 mm at both concentrations of the extract. Therefore, the extract of cashew nut shell liquid (A. occidentale) showed a potential antimicrobial effect against E. faecalis strains.

The Potential Clinical Applications of a Microfluidic Lab-on-a-Chip for the Identification and Antibiotic Susceptibility Testing of Enterococcus faecalis-Associated Endodontic Infections: A Systematic Review.

This systematic review evaluated the potential clinical use of microfluidic lab-on-a-chip (LOC) technology in the identification and antibiotic susceptibility testing of E. faecalis in endodontic infections. The search methodology employed in this review adhered to the PRISMA guidelines. Multiple scientific databases, including PubMed/MEDLINE, SCOPUS, and SCIELO, were utilized, along with exploration of grey literature sources. Up to September 2023, these resources were searched using specific keywords and MeSH terms. An initial comprehensive search yielded 202 articles. Ultimately, this systematic review incorporated 12 studies. Out of these, seven aimed to identify E. faecalis, while the remaining five evaluated its susceptibility to different antibiotics. All studies observed that the newly developed microfluidic chip significantly reduces detection time compared to traditional methods. This enhanced speed is accompanied by a high degree of accuracy, efficiency, and sensitivity. Most research findings indicated that the entire process took anywhere from less than an hour to five hours. It is important to note that this approach bypasses the need for minimum inhibitory concentration measurements, as it does not rely on traditional methodologies. Microfluidic devices enable the rapid identification and accurate antimicrobial susceptibility testing of E. faecalis, which are crucial for timely diagnosis and treatment in endodontic infections.

Nanobiomaterials in the Management of Oral Biofilms

The oral cavity inhabits diverse microorganisms with members of all age groups including children being associated with oral infections. Bacteria being the principle component of this resident microflora along with the diverse group of other species reflect the wide range of viscerously derived nutrients, the heterogenous habitats for colonization contributing to the survival of the biofilm. Biofilms constitute surface- adherent communities of microorganisms like Streptococcus mutans along with other bacterial species embedded in an extracellular matrix material. The commensal relationship between the host and the microflora can be disrupted in numerous ways, resulting in compromised oral health causing conditions like dental caries and endodontic infections, gingival and periodontal conditions, oral candidiasis and peri-implantitis. Biofilm-related infections prove to be a major threat from both an economical and health perspective. Innovative treatment options remain limited despite of advancements in understanding the mechanisms of biofilm formation. The concept of nanotechnology is based on controlling atoms on an individual basis and creating structures less than 100 nm (10_7 m) in size thereby greatly influencing the properties. Incorporation of metals and other nanoparticles with polymers and coating of surfaces provide antimicrobial and anti-adhesive benefits within the oral cavity. Therefore, this paper seeks to throw light into the current advancements in nanoparticle mediated treatment approaches of oral biofilms and its future implications in pediatric dentistry. Keywords: Biofilm, Oral Cavity, Metal Oxides, Nanoparticles, Reactive Oxygen Species, Antibiofilm Efficacy

Components and outcome of triple antibiotic paste and its application in endodontic infections

In the field of endodontic therapies, the use of antibiotics, especially in the form of root canal medications, plays a pivotal role in ensuring successful treatment outcomes. This review examines the role of triple antibiotic paste (TAP) in such therapies, delving into its composition, application, and effects on endodontic infections. TAP, a combination of metronidazole, ciprofloxacin, and minocycline, targets the diverse microbial flora in odontogenic infections. Its local application within the root canal space proves more effective than systemic administration, significantly reducing microbial count and aiding in tissue regeneration and disinfection. However, the use of TAP is not without challenges, as it can cause tooth discoloration, particularly due to minocycline, and raise concerns about antibiotic resistance and long-term biocompatibility. This study, conducted through a comprehensive literature search, evaluates the efficacy of TAP, its impact on tooth structure, and its role in maintaining the vitality of diseased pulp. The findings highlight TAP’s significant role in endodontic treatments, emphasizing its benefits in achieving therapeutic goals while acknowledging the need for careful consideration of its drawbacks.

Triple antibiotics: A synergistic approach to combating infection

The utilization of Triple Antibiotic Paste (TAP) in dentistry has emerged as a significant development in endodontic and odontogenic infection management. With increasing cases of odontogenic infections, particularly in the context of the complex root canal anatomy, the selection of appropriate medicaments and disinfectants has become imperative. (1) In situations where conventional manual preparation and irrigation prove inadequate, TAP stands out as an intracanal disinfectant comprising a combination of three antibiotics, exhibiting a synergistic antimicrobial effect against a wide spectrum of microorganisms. This review outlines the multifaceted applications of TAP in dentistry, from its composition and clinical utility to its potential in preserving the vitality of diseased pulp. It also acknowledges the limitations and drawbacks associated with TAP's application, emphasizing the need for precise administration. Furthermore, it discusses TAP's role in primary teeth, expanding its scope beyond conventional endodontics. This research investigation explores the latest insights and considerations surrounding the "triple antibiotic paste" (TAP) and its applications in the field of dentistry, with a particular focus on endodontics.

Increased IL-12p70 and IL-8 Produced by Monocytes in Response to Streptococcus spp. and Actinomyces spp. Causals of Endodontic Primary Infections.

We sought to evaluate the effect of endodontic-causative microorganisms of primary infections on mononuclear cells such as CD14+, CD4+, CD8+, CD19+ and Tregs Foxp3+. Facultative anaerobic microorganisms were isolated from radicular conducts and peripheral blood samples, which were taken from patients with primary infections. Cellular cultures were performed with peripheral blood mononuclear cells (PBMC) with and without Actinomyces spp. and Streptococcus spp. during 48, 72, and 96 h of contact in culture (concentration 5 × 105 cells/well) in a round plate bound with 48 wells. Later, PBMC was collected for analysis by flow cytometry, with the monoclonal antibodies αCD14, αCD4, αCD8, αCD19 and αFoxp3, and acquired using an FACSCanto II cytometer. The supernatant of cellular cultures was analyzed for the quantification of inflammatory cytokines. Data analysis was performed in FlowJo v10.8.2 and FCAPArray software, and statistical analysis was performed using GraphPad v5.0. software. We observed an increase in the percentage of CD14+ cells in patients at different hours of cellular culture in the presence of both Actinomyces spp. and Streptococcus spp. microorganisms, compared to healthy controls. This study demonstrates the role played by the innate immune system in the pathogeny of endodontic primary infections, explaining the effects that generate the more common microorganisms in this oral pathology.

Does aPDT reduce bacterial load in endodontic infected teeth? A systematic review and meta-analysis.

This systematic review investigated whether antimicrobial photodynamic therapy (aPDT) after chemomechanical root canal disinfection (CD) yields a greater microbial load reduction than only CD. An electronic literature search was conducted on four databases up to November 2022, with no language or publication date restrictions. Randomized and non-randomized clinical trials were included if participants had a primary endodontic infection in permanent teeth, and if microbial loads before and after using aPDT were compared. Two researchers independently screened titles and abstracts to determine study eligibility. Assessments included risk of bias and methodological quality. This review was registered in PROSPERO (CRD42020181783). Eight studies were included in the qualitative analysis, and six were eligible for meta-analysis. In the random effects model, aPDT significantly improved the results of root canal disinfection when compared with standard protocols for cleaning and shaping (p = 0.04, 95% CI -1.72, -0.05). Subgroup analysis suggested that aPDT has a better effect on reducing the load of anaerobic microorganisms (p = 0.003, 95% CI -3.36, -0.69). The use of aPDT as an adjunct to chemomechanical disinfection promotes additional reduction of the microbial load and, therefore, seems to improve the results of root canal treatments in permanent teeth with a primary endodontic infection. However, certainty of evidence should be improved.

Functionalized surface of PLGA nanoparticles in thermosensitive gel to enhance the efficacy of antibiotics against antibiotic resistant infections in endodontics: A randomized clinical trial

Enterococcus faecalis plays the key role in endodontic infections and is responsible for the formation of biofilm on dentin, which causes a resistance against periradicular lesions treatment, consequently the aim of this study is to use nanoparticles entrapping anibacterial agents coated with chitosan that in authors previous study showed a successful in vitro biofilm inhibition, additionally incorporated in thermoresponsive gel.to benefit nanoparticles` small size, and the positive charge of their surfaces that binds with the negatively charged surface of bacterial cell causing its destruction, in addition to the sustained release pattern of the drug based nanoparticles in gel. Therefore, Ciprofloxacin hydrochloride (CIP) encapsulated in PLGA nanoparticles coated with chitosan (CIP-CS-PLGA-NPs), in addition to free CIP, were incorporated in Pluronic® 407/188 to form thermosensitive gels (F1) and (F2), respectively. The thermosensitive gels were tested with regards to rheology, gelling temperature and the release pattern of the drug. A clinical study of the efficacy of F1 and F2 as antibacterial treatments was conducted on patients followed by a comparative studies against CIP and Ca(OH)2 pastes in terms of biofilm inhibition assay and total bacterial reduction count and percent.The results revealed that F1 and F2 exhibited gelation temperature of 36.9 ± 0.3 °C and 36.0 ± 0.4 °C, viscosity was 15,000 ± 360.6 and 7023.3 ± 296.8 cP respectively. The cumulative release of F1 and F2 after 72 h was 50.03% ± 0.7345 and 77.98% ± 3.122 respectively. F1 was the most efficient treatment against recurrent E.faecalis infection in endodontics that was evident by the highest total bacterial reduction count and percent and biofilm inhibition percent that were recorded in the group treated with F1followed by the group treated with F2. Nanocarriers succeeded in carrying the drug deeply in the root canal and sustaining its effect to abolish the obstinate E. faecalis recurrent infection and its biofilm formation.

Novel strategies enhancing endodontic disinfection: antibacterial biodegradable calcium hydroxide nanoparticles in an ex vivo model

Due to the high failure rates associated to endodontic disinfection, this study aimed to investigate the antibacterial properties of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with Ca(OH)2 for endodontic disinfection procedures. Ca(OH)2 NPs production and physicochemical characterization were carried out as well as multiple antibacterial tests using three bacterial strains and an ex vivo model of endodontic infection with extracted human teeth. Agar diffusion test and broth dilution determined the inhibition growth zones (n=5) and the minimal inhibitory concentration (MIC, n=5), respectively. Cell viability was assessed using Live/Dead staining with confocal microscopy (n=5). Data was analysed using ANOVA followed by post-hoc analysis. After 24 hours of incubation, Ca(OH)₂ NPs demonstrated a MIC of 10 µg/mL for Porphyromonas gingivalis (p<0.001) and Enterococcus faecalis and 5 µg/mL for Fusobacterium nucleatum (p<0.001). Although the agar diffusion test did not exhibit any inhibition for Ca(OH)2 nor for Ca(OH)₂ NPs area probably due to the buffering effect of the agar medium. However, the antibacterial capacity was confirmed in an ex vivo model, where instrumentalized teeth were infected with Enterococcus Faecalis and treated after 28 days of culture. A significant reduction in bacterial metabolic activity was confirmed for Ca(OH)2 NPs (40% reduction with a single dose) and confirmed by Live/Dead staining. In conclusion, Ca(OH)₂-loaded PLGA NPs present promising antibacterial efficacy for endodontic disinfection procedures.

Investigating the effect of Er,Cr:YSGG laser agitation of sodium hypochlorite on the removal of mature biofilm in the complex root canal systems using atomic force microscopy.

Endodontic infections caused by remaining biofilm following disinfection with chemical fluids encourage secondary bacterial infection; hence, employing laser pulses to activate the fluids is advised to improve microbial biofilm clearance. This study investigated the performance of Er,Cr:YSGG laser in photon-induced photoacoustic streaming (PIPS) agitation of 5.25% sodium hypochlorite (NaOCl) to enhance the removal of mature Enterococcus faecalis (E. faecalis) biofilms in complex root canal systems. The mesial roots of the lower first and second molars were separated and inoculated with E. faecalis bacteria for 30 days. The roots were irrigated with 5.25% NaOCl, some of them were agitated with passive ultrasonic irrigation (PUI), and the other roots were agitated by Er,Cr:YSGG laser using PIPS at 60 µs/pulse, 5 Hz, and 0.25, 0.5, 0.75, 1, and 1.25 W. An atomic force microscope (AFM) was used as a new method to obtain the results in the isthmus area; the results that have been obtained from each group were compared with each other. ANOVA was utilized to compare the means of the test groups. Based on the AFM and SEM analyses, laser agitation and passive ultrasonic activation groups have shown higher antimicrobial efficacy than the conventional syringe irrigation group (P<0.05). Based on the findings of this investigation, the agitation of 5.25% NaOCl solution by Er,Cr:YSGG laser in PIPS at (60 µs/pulse, 5 Hz, 1.25 W) offers better mature bacterial biofilm removal in the mesial root of lower human molars than the same irrigant with syringe irrigation and passive ultrasonic activation technique.

Novel Antibacterial and Biocompatible Nanostructured Gels Based on One-step Synthesis as a Potential Disinfectant for Endodontic Infection Control

AimThe objective of this study was to develop nanostructured gels as biocompatible intracanal disinfectants by one-step microwave radiation-assisted synthesis. MethodsPolyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) were used as a support network, and polyethylene glycol (PEG) was used as a reducing agent. The gels were characterized by measuring the swelling ratio (SR) and rheological properties and by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The antibacterial effects of each gel were evaluated against the endodontic clinical strain Enterococcus faecalis. Then, the viability of the 21-day mature multispecies bacterial biofilm was assessed using confocal microscopy in an ex vivo model, where the biofilm was exposed to the mix of nanogels. The cell proliferation, viability, and morphology of human periodontal ligament (HPDL) cells were quantified using a real-time IncuCyte® S3 Live-Cell System. Viability was measured by confocal microscopy using an ex vivo model exposing a 21-day mature multispecies bacterial biofilm to the mix of nanogels. ResultsThe antibacterial activity of the gels coincided with the superficial characterization and the solubility of the gel in the growth medium. Gels with higher viscosity (327.85-980.58 Pa s), higher dissolution (42-70%SR), and lower porosity (no porosity and 611.63 nm) showed excellent antibacterial activity against E. faecalis. Despite their physicochemical characteristics, CuNPs gels showed greater effectiveness against E. faecalis.These nanostructured gels with high PVA concentrations promote HPDL cells proliferation while still exerting antibacterial properties. Mix of nanogels showed an increase non-viable cells biomass from at of application. ConclusionsThe use of biocompatible polymers influences the physicochemical, bactericidal, and cytotoxic response, making these materials potential disinfectant agents against resistant bacteria with good biocompatibility and improved HPDL cells proliferation.

Multispecies oral biofilm and identification of components as treatment target

Endodontic infections involve a multispecies biofilm, making it difficult to choose an antimicrobial treatment. Characteristics such as the pathogens involved and number of microorganisms, nutrients, material surface to develop the biofilm, flow and oxygenation conditions are important for biofilm development using in vitro models. ObjectiveTo develop a standardized biofilm model, which replicates the main features (chemical, microbiological, and topographical) of an infected root canal tooth to detect components as treatment target. DesignClinical strains of Enterococcus faecalis, Candida albicans, and Actinomyces israelii were isolated, and a multispecies biofilm was developed using continuous laminar flow reactors under anaerobic conditions in human dental roots. The microbiological composition was determined by counting colony-forming units and scanning electron microscope micrographs. In addition, the chemical composition of the exopolymeric matrix was determined by vibrational Raman spectroscopy and liquid chromatography of biofilm supernatant treated with enzyme. ResultsE. faecalis turned out to be the main microorganism in mature biofilm, this was related to the presence of β-galactosidase detected by vibrational Raman spectroscopy. After the enzymatic treatment of the extracellular polymeric substance, the presence of mannose and glucose was established. ConclusionsThe present work contributes to better understanding of standard conditions to develop a multispecies biofilm in human dental roots, which could have an impact on the generation of new root canal disinfection techniques in endodontic pathologies.

Lipophosphonoxins-A Novel Group of Broad Spectrum Antibacterial Compounds.

Lipophosphonoxins (LPPOs) represent a new group of membrane-targeting antibiotics. Three generations of LPPOs have been described: First-generation LPPOs, second-generation LPPOs, and LEGO-LPPOs. All three generations have a similar mode of bactericidal action of targeting and disrupting the bacterial cytoplasmic membrane of prokaryotic cells, with limited effect on eukaryotic cells. First-generation LPPOs showed excellent bactericidal activity against Gram-positive species, including multiresistant strains. Second-generation LPPOs broaden the antibiotic effect also against Gram-negative bacteria. However, both first- and second-generation LPPOs lose their antibacterial activity in the presence of serum albumin. LEGO-LPPOs were found to be active against both Gram-positive and Gram-negative bacteria, have better selectivity as compared to first- and second-generation resistance to LEGO-LPPOs was also not observed, and are active even in the presence of serum albumin. Second-generation LPPOs have been studied as antimicrobial additives in bone cement and as nanofiber dressing components in the treatment of wound infections in mice. Second-generation LPPOs and LEGO-LPPOs were also tested to treat ex vivo simulated endodontic infections in dental root canals. The results of all these studies were encouraging and suggested further investigation of LPPOs in these indications. This paper aims to review and compile published data on LPPOs.